Incandescent lamp



(No Model.)

P. 0. ROGKWELL.

NCANDBSCENT LAMP- No. 430,485. Patented June 17, 1890.

NITED STATns Arent Fries.

INCANDESCENT LAMP.

SPECIFICATION forming part of Letters Patent No. 430,485, dated June 17,1890.

Application filed February 28, 1890. Serial No. 342,170. (No model.)

To CLM whom it may concern:

Be it known that I, FREDERICK C. ROCK- WELL, a citizen of the UnitedStates, residing at Hartford, in the county ot Hartford and State ofConnecticut, have invented certain new and useful Improvements inIncandescent Lamps, of which the following' is a full, clear, and exactspecification.

The improvement relates to the bases of incandescent electric lamps; andthe object is to so construct a base for such a lamp thatit may beformed lirm and strong of a material which is cheaper and more easilymanipulated and which possesses more desirable insulating andheat-non-conducting qualities than the material now used,thisconstruction adapting the base to be more securely held to the end of aglobe of a lamp than prior bases.

Referring to the accompanying drawings, Figure l is a side view of oneform of lamp providedwith my improved base. Fig. 2 is a plan view of theblank from which the base is formed. Fig. 3 is a view on enlarged scale,in central vertical section, of the base. Fi g. 4. is an end view of thebase. Fig'. 5 is aside view of another form of lamp provided with myimproved base. Fig. G is a plan view of. the blank used in forming thebase of the lamp last shown. Fig. 7 is a view, on enlarged scale, incentral vertical section, of the base shown in Fig'. 5. Fig'. S is aside view of still another' form of base.

In the views, the letter aindicates the globe, and l) the base of alamp. Previously such bases have been formed of thin brass, which hasbeen first drawn to a cup shape from a i'lat sheet by the successiveaction of dies, or which may have been spun to a cup shape over amandrel, and then had the closed end removed. The shell is then securedto the end of the globe by plaster-ofparis or a similar cement. Thismethod of formation Wastes much material, the tools are quickly dulledand worn out, much time and labor is expended in the numerous handlin gsof the base, and in a short time the cement loosens its grasp on thesmooth interior of the base thus formed, so that the globe is liable todrop out.

In forming my improved base h a strip of paper or similar materialsuitably sized or treated is cnt to the proper shape and passed betweenrolls that are preferably heated,

which crimp, flute, or corrugate a portion of the strip. These rolls maybe so formed that the crimps, corrugations, or tintes may be` made toextend completely across the width of the strip, or only partly across,and enough length of the strip is, crimped to reach at least once aroundthe base when it is formed. This partially-erimped blank is rolled on asuit ably shaped former, beginning with the crimped end 1) and ending'with the smooth end o, into a cylinder of the desired size of the base,the uncrimped portion h forming the smooth exterior wall for receivingthe key-socket, and the crimped portion lr forming the interior wall,which greatly stiffens and strengthens the smooth outside wall of thebase. The smooth end h of the blank may be made of such length that itcan be wrapped around the crimped portion b several times, if desired;or the interior crimped portion and the exterior smooth portion may beformed in two separate cylinders, which can be placed one within theother and glued or cemented together,thus producing the same effect ofstrengthening the smooth exterior wall by a crimped interior. The basethus formed is then dipped into or coated with a solution, preferably adissolved gum, possessing' a high degree of insulating andheat-nonconducting capacity, which, when hardened by heat or pressure,so stiii'ens that a rigid and lirm base is formed which possessessuperior insulating and heat-non-conducting qualities.

A piece of insulating material d, bearing the usual conductors forconnecting the socket-conductors with the leads to the iilament, isplaced in one euch-and the base secured to the end of the globe by asuitable cement e, as plaster-of-pai'is, which is molded into the basearound the end of the globe in a moist condition. It will be impossiblefor the base to work loose and turn after the cementing material hasdried, as occurs with the prior bases, as the cementing material packsand becomes embedded between the ridges of the lintes or corrugations ofthe interior of the base to which the cement more lfirmly adheres thanto the smooth metallic interior of the prior bases.

The spaces c between the inner corrugated wall h and the smooth exteriorwall h ofthe IOO rial may dry out more quickly. A base thus b ase may hefilled with the insulating material with which the base is treated; orperfo-y rations c may be made through the corrugations, so the celnenting materiale will flow into the spaces and stiiien the base, as Wellas more firmly hold the parts together7 or the spaces c may be leftopen, so as to form airehambers in order that the cementingmatecorrugatcd or indented can be cheaply formed of inexpensive materialand will possess sufiicicnt rigidity and strength, and be insulating andheat-non-condnoting, which are qualities much desired in the bases oflamps of this nature.

I claim as my inventionl. A base for an incandescent lamp, con,- sistingof superimposed layers of a thin nonconducting material, the inner layerof said material being corrugated r indented and the exterior smooth,substantially as specified.

2. A base for an incandescent lamp, con sisting of layers of a thinnon-conducting material Wrapped about each other, a portion of the innerWraps of said material being corrugated or indented, substantially asspeciied.

FREDERICK C. ROCKVVELL.

Witnesses:

H. R. WILLIAMS, A. F. LANGDON.

